Field of the Invention
The invention relates to an energy system for buildings according to the preamble of claim 1.
Solar energy systems have been known for a long time and are increasingly used for energy saving. In particular, the heat produced by direct solar irradiation is used in solar absorbers for the heating or preheating of service water, and also in heating systems. It is also already known to first store the heat energy which is not immediately required, for example by heating water in a tank. The heat energy can later be extracted from the accumulator by means of heat exchangers.
Heat insulation also plays an important part in the energy balance of a building, in addition to the energy supply in the form of solar energy or combustion energy. Important advances have been made here by heat insulating materials in the region of the outer walls and of the roof. However, further improvements of the heat balance are desirable, and the invention therefore has as its object to make such improvements possible. The attainment of the object is characterized in claim 1. In common with other features which are described in more detail hereinbelow, it is based on physical fundamentals.
The solar absorber according to feature (a) is substantially more cost-effective than known solar absorbers, which are installed additionally on the roof in the form of plates. By the laying of tubes or pipes between the roof covering, which generally consists of roofing tiles, and the insulating layer, no additional constructional materials are required other than the tubes or pipes. Furthermore, the external appearance of the building is not detracted from.
The division of the solar absorber according to feature (b) into at least two regions, each with its own liquid circuit, insures that the liquids heated in the absorber can be used separately according to their respective temperatures, instead of producing an average, mixed temperature at the output of the solar absorber. For example, the liquid with the higher temperature can also then further boost a heat accumulator, even when the average mixed temperature is below the temperature of the heat accumulator.
The solid heat accumulator according to feature (c) is likewise divided into at least two regions. The central region then has the higher temperature. The regions with lower temperature can then also be further loaded by means of absorber liquids when their temperature is lower than that of the central region. A very good energy balance can thereby be attained. The feature (e) describes more precisely the operation controlled by temperature sensors. Correspondingly, the feature (f) describes more precisely the operation by means of which heat energy is extracted from the accumulator regions for heating the building.
Further developments of the invention are the subject of the dependent claims. Thus it can be provided that the solar absorber is divided into at least three regions, which are associated with differently oriented roof sections. This enables an even better separation between the different temperature regions to be achieved, in dependence on the geographical orientation of the roof sections. The tubes or pipes of the solar absorber can suitably be laid in troughs or grooves of meandering form in the insulating layer. They are then securely mounted without additionally increasing the thickness of the insulating layer or of the roof covering.
In an advantageous manner, the outer region of the solid heat accumulator is widened out downward in the shape of a funnel, and the sections which are located outside the contour of the building are covered by a heat-insulating layer. In this manner, the heat rising from the Earth's interior can be used to a greater extent. Even in winter, with temperatures below the freezing point, the ground is substantially warmer because of the rising energy. For example, an average temperature at a depth of 2 m, with a free surface, is about +7 to +9.degree. C. Under the building, the temperature at this depth amounts to at least about +14 to +16.degree. C. The same effect for the use of the Earth's heat results, for example, from covering with plantings, which prevent the Earth's rising heat from immediately radiating away again. Frost protection can be achieved in this manner.
The solid heat accumulator can advantageously be divided into three regions, namely the central region, a middle region surrounding the central region, and an outer region surrounding the middle region. An even finer graduation of the temperature levels of the individual accumulator regions can thereby be attained.
The outer region of the solid heat accumulator can furthermore be surrounded by a peripheral accumulator region. The recovery of further heat energy can thereby be made possible. In particular, however, the peripheral accumulator can also be used to obtain cooling in the building by means of the cold liquid.
By means of the different accumulator regions, with respectively lower temperatures, which surround the central region in a shell shape but are as far as possible open downward, the result is achieved that the central region is better insulated and loses less heat, because the surrounding middle region is less cold than the ground. The corresponding relationship also holds for the outer accumulator region. The lateral heat outflow of the accumulator is largely compensated by the funnel-shaped configuration of the outer accumulator region. Moreover, even the smallest solar heat with a lower temperature can still be used by the division of the accumulator into several regions, in that the liquid from the solar absorber regions is conducted into the outer or peripheral region of the solid accumulator. In this manner, even in winter at absorber temperatures between 8.degree. C. and 15.degree. C., the solar energy can be used by loading the peripheral accumulator region. The "protective jacket" around the central accumulator region is improved by heating in this manner. Altogether, it is thereby possible to bridge over the dreaded energy hole in the months of December through March in the conventional solar heating technology.
At least a portion, or all, of the outer walls appropriately each has a tube or pipe system through which liquid flows in order to transfer heat from the wall to the liquid or vice versa, wherein the tube or pipe system can be connected in a circuit with a pump for the liquid. In this manner, a heat exchange can take place between the outer walls on the sun side and the shade side. Such a "north-south equalization" can substantially improve the heat economy of the building when heat from the hot south wall is delivered to the cold north wall in summer. This leads in winter also to a more uniform heat distribution in the building. The outer walls of the building can appropriately be additionally provided on the outside with a transparent, absorption-increasing coating or facing, in order to obtain a better energy yield. Such a transparent heat insulation is also denoted by "TWD".
A further development of the invention provides for the tube or pipe system of the outer walls of the building to be connected via temperature-controlled valves to the liquid circuits of the regions of the solid heat accumulator. Then in summer the energy radiated in can be stored, and furthermore cool liquid, in particular from the peripheral accumulator, can be supplied for the cooling of the tube or pipe systems in the outer walls. In winter, the pipe systems of the outer walls of the building are advantageously used as a heating system. Moreover, additional heat energy can be recovered in winter, particularly in the case of a coating or facing with absorption-increasing material (TWD).
The tube or pipe systems in the outer walls of the building make possible numerous air conditioning processes and compensation functions and are therefore also termed an "outer wall air conditioning and compensation system" (AKK system). There belong to the functions the north-south equalization already mentioned, air conditioning in the summer months by taking away excess solar heat, a compensation for heat transmission losses in the winter months by space heating by means of stored energy, and also the function as a wall heating system. A ring conduit can suitably be laid for this purpose in a solid floor, and branch ducts can lead from it to the outer walls of the individual spaces. Thermostatic valves in these branch ducts permit individual temperature regulation of each individual space. A large-surface heating of this kind was already known in Roman times as hypocaust heating, and served for the heating of villas and baths. The temperature adjustment of historic protected buildings, with thermal drying of masonry at the same time, is also made possible by such a system. Solid accumulators may then usually be installed in the cellars of such buildings. Solar absorbers can be retrofitted during roof repairs without externally detracting from the appearance of the building. If necessary, solar absorbers can also be placed outside the building, or if necessary one can manage without the absorber.
The AKK system can also prevent dew point problems in endangered regions of structural members, by maintaining dryness, and by condensation protection in regions exposed to high humidity or in regions in contact with the ground. Finally, a low power (few kW) emergency and additional heating system can be connected to the circuits of the AKK system, for extreme weather conditions, or even for habits of use which lack energy discipline and which cannot be calculated.
A service water heat exchanger can be connected by means of temperature controlled valves, as a bypass and with priority, to that region of the solar absorber which has the highest temperature. A heating or preheating of the service water to more than 40.degree. C. can be obtained in this manner. The solid heat accumulator appropriately contains as accumulator material a packing of broken stone or gravel, at least 60 cm thick, because of its low cost and high specific heat. In addition, in the central region of the solid heat accumulator, a layer can be formed of steel beams, auto cubes (old autos compressed into cubes), and similar material with the highest possible specific heat. Disposal of such materials is thus effected at the same time, and may even be paid for.
The heat accumulator as a whole, or particularly its central region, can be insulated on the ground side by a heat insulating layer. An energy loss from the regions of the heat accumulator which have a higher temperature than the ground below them is thereby hindered. In the outer region, and particularly in the peripheral region, heat insulation may on the contrary be inappropriate, when the heat rising from the Earth's interior arrives with a higher temperature than that of the respective accumulator region. Water or an antifreeze agent of the usual kind is used as the liquid for all the circuits.
Circulation pumps may possibly be necessary in the individual regions of the solar absorber, of the solid heat accumulator, and of the building heating system which is appropriately designed as floor heating or outer wall heating; the circulation pumps are not described in detail here, since a skilled artisan can judge without difficulty their respective use in each individual case.
Modem buildings are so well sealed that periodic ventilation is indispensable. However, this leads to heat losses, or to an undesired additional heat inflow in summer. A development of the invention proposes that openings for air interchange are provided, particularly in the window frames, and heat exchangers in them are connected to the tube or pipe systems of the building outer walls and have fins through which the liquid flows. The air flowing in winter can then be preheated by the heat exchangers, with recovery of the heat, and in summer a corresponding cooling of the inflowing air can be obtained.
Another solution of the ventilation problem proposes that an outer ground duct arranged around the peripheral heat accumulator region and an inner intake channel running in the solid heat accumulator are provided. Controlled by a multi-way valve, cooled air can be sucked in through the outer duct in summer operation, and in winter operation preheated air can be sucked in through the inner duct and conducted into the building.